On the materials and processes for additive metallurgy

这项提案由两部分组成，这两部分源于NSERC以前资助的赠款所获得的丰富经验。*提案的第一部分是一种以非常规方式应用粉末冶金的创新方法。到目前为止，粉末冶金制造的创新零件都是通过添加合金来制造的。然而，在需要两种不同金属的不同行为的情况下，例如可以承受乙二醇基冷却剂的腐蚀的铝和非常容易受到冷却剂侵蚀的镁，需要一种新的创新方法。在3D金属印刷添加剂制造的开发中也出现了类似的情况，其中主材料可能容易受到流经部件的流体的影响，并且循环管道必须由与制造部件的主合金兼容的材料建造，并且能够承受流体的腐蚀作用。这项研究旨在解决传统的粉末冶金和新兴的3D金属添加剂制造的问题，通过研究由这两种不同材料制成的简单试件，并用包括电化学在内的传统表征技术来表征它们的界面。这将导致由铝和镁等两种不同金属制成的较轻部件复合材料的建造，这些金属目前在一些汽车发动机机体中使用。*本提案的第二部分涉及研究开发一种新型的金属填充含氟聚合物复合材料，例如PVDF，其中包含一种金属填料，该金属填料由化学镀TiN的铜颗粒制成，从而形成核壳结构。这一创新之处在于使用核壳结构的镀锡铜粉作为金属填充物。铜在加工过程中不再受到氧化的影响。复合材料的制备采用注塑成型工艺，将有机聚合物与包覆TiN的铜粉混合后热压成型。铜芯的作用是在所制造的复合材料内创建导电路径，从而增加所制造的材料的导电性，而铜(芯)上的TiN涂层(壳)在复合材料制造期间保护铜颗粒免受氧化。在成型过程中防止氧化是必要的，因为氧化铜表面层降低了粉末的导电性。此外，锡层扩散到邻近的铜中，产生环境稳定的金属间化合物相。这种核壳结构可用于许多工业应用，例如电路保护、天线、汽车和数据通信。这一方案是我们实验室先前开发的化学镀和核壳技术的创新组合。*因此，这两种创新方法通过传统技术来生产改进的产品。

This proposal consists of two parts resulting from the vast experience obtained by previous NSERC supported grants.***The first part of the proposal is an innovative approach to apply powder metallurgy in an unconventional way. Until now innovative parts made by power metallurgy are made by alloying additions. However, in cases that require different behaviour by two different metals, such as aluminum which can withstand the corrosion by glycol based coolant and magnesium which is very vulnerable to coolant, a new innovative approach is needed. Similar cases arise in the development of 3Dmetal printing additive manufacturing where the main material may be vulnerable to a fluid which is circulated through the part and the circulation pipe must be constructed from a material which is compatible with the main alloy of which the part is made and can withstand the corrosion action of the fluid. The proposed research is to address the problem of traditional powder metallurgy and the emerging 3Dmetal additive manufacturing by studying simple specimens made of the two different materials and characterize their interface by traditional characterization techniques including electrochemistry. This will lead to construction of the lighter parts composites made by two dissimilar metals such as aluminum and magnesium as they presently utilized in some automotive engine blocks. ***The second part of this proposal relates to the research to develop a novel metallic filled fluoropolymer composite such as PVDF containing a metallic filler that is made of copper particles coated electrolessly with tin resulting in a core-shell structure. The novelty is related to the use of core-shell structured tin coated copper powders as metallic fillers. Copper is no more exposed to oxidation during processing. The composite will be fabricated by injection molding process where the organic polymer and tin coated copper powders are mixed followed by hot compression. The role of copper core is to create an electrical conduction path within the fabricated composite hence increasing the electrical conductivity of the fabricated material, whereas the tin coating (shell) on copper (core) protects the copper particles from oxidation during the composite fabrication. The protection from oxidation during the molding process is necessary because the copper oxide surface layer decreases the electrical conductivity of the powders. Additionally, the tin layer diffuses into the adjacent copper giving rise to environmentally stable inter-metallic phases. The core-shell structures can be beneficial to many industrial applications, for example circuit protection, antennas, automotive, and data communication. This proposal is the innovative combination of electroless plating and core-shell technique both developed previously in our laboratory.***Thus two innovative approaches by traditional techniques to produce improved products.